Automatic update for previous versions (permissions)

There's no built-in option for this as permissions are version-specific by design: this way you can control the visibility through the object's lifecycle and each user can only see those versions they are supposed to see.

If the issue is specifically about the visibility of the comments, as a workaround you could perhaps store all the comments in a property on the metadata card so that users who get access to the object later can view the full comment history from that property. You may need to write an event handler or some other custom extension for this comment collection (copying from the built-in Comment property to your own comment property).

As many times so far - thank you for confirmation Joonas :) 

We supposed this won't be possible without us having to write some custom solution. Anyway, it is quite reasonable request from the end users... Case is next - they are lawyers and one person works on a contract for 6 months. Contract is signed and next year comes renewal and someone else is assigned to contract. That new person would like to see all changes, comments, etc. to better understand how they came to conclusion. I know it is against the M-Files architecture of versioning and permissions, still customer request makes sense. 

Once again - thanks! 

Are there a lot of contracts? I'm just thinking if it would be possible to utilize user groups somehow in the permissions so that the person responsible for the contract would be added to a contract-specific user group that has the permission to view the full history of the document. This user group management could be done automatically by a custom vault application for instance based on the contract owner specified in the document metadata.

Good idea but there will be a lot of contracts, not sure if this is a way to go in our case.